Vehicle, control apparatus for vehicle, and control method for vehicle

Abstract

An electronic control unit performs lockup clutch engagement control in the sequence of fast fill control, constant-pressure standby control and command pressure raising control, and starts the lockup clutch engagement control from that one of the fast fill control and the command pressure raising control which is later in sequence than the other, as a command pressure for a control oil pressure at a transition time point for making a transition to the lockup clutch engagement control rises, in making the transition to the lockup clutch engagement control during the lockup clutch release control. Therefore, when the command pressure for the control oil pressure is equal to or higher than a predetermined value that is needed to carry out packing for narrowing a pack clearance of a lockup clutch, the lockup clutch engagement control is started from the command pressure raising control.

What is claimed is: 
     
       1. A vehicle comprising:
 a transmission; 
 a fluid coupling provided between the transmission and a power source; 
 a lockup clutch configured to directly couple an input member and an output member of the fluid coupling by supply of a control oil pressure to a control oil chamber in the fluid coupling; and 
 an electronic control unit configured to perform lockup clutch release control for lowering a command pressure for the control oil pressure to release the lockup clutch, 
 the electronic control unit being configured to perform lockup clutch engagement control for raising the command pressure for the control oil pressure to engage the lockup clutch, 
 the electronic control unit being configured such that the lockup clutch engagement control is performed in sequence of fast fill control, constant-pressure standby control and command pressure raising control, and 
 the electronic control unit being configured to start the lockup clutch engagement control from one of the fast fill control and the command pressure raising control which is later in sequence than the other, as a first command pressure rises, in making a transition to the lockup clutch engagement control during the lockup clutch release control, the first command pressure being the command pressure for the control oil pressure at a transition time point for making the transition to the lockup clutch engagement control. 
 
     
     
       2. The vehicle according to  claim 1 , wherein
 the fast fill control is control for raising the command pressure for the control oil pressure to a first predetermined value set in advance and supplying the control oil pressure to the control oil chamber, 
 the constant-pressure standby control is control for making the command pressure for the control oil pressure equal to a second predetermined value set in advance and causing the command pressure for the control oil pressure to stand by for a predetermined time, the second predetermined value is lower than the first predetermined value, and 
 the command pressure raising control is control for raising the command pressure for the control oil pressure in accordance with a torque capacity that is needed to engage the lockup clutch. 
 
     
     
       3. The vehicle according to  claim 1 , wherein
 the electronic control unit is configured to start the lockup clutch engagement control from the command pressure raising control when the first command pressure is equal to or higher than a third predetermined value that is needed to carry out packing for narrowing a pack clearance of the lockup clutch. 
 
     
     
       4. The vehicle according to  claim 3 , wherein
 the lockup clutch includes 
 a friction plate, 
 a piston configured to press the friction plate by supply of the control oil pressure to the control oil chamber, 
 a return spring configured to urge the piston in such a direction as to move away from the friction plate, and 
 the electronic control unit is configured to start the lockup clutch engagement control from the fast fill control when the first command pressure is equal to or lower than a value of a pressing force of the piston, the pressing force of the piston is generated by the command pressure and the value of the pressing force of the piston is equal to a value of an urging force of the return spring. 
 
     
     
       5. The vehicle according to  claim 4 , wherein
 the electronic control unit is configured to perform the lockup clutch release control until the command pressure for the control oil pressure once becomes equal to zero and then to start the fast fill control, in performing the lockup clutch engagement control from the fast fill control. 
 
     
     
       6. The vehicle according to  claim 4 , wherein
 the electronic control unit is configured to start the lockup clutch engagement control from the constant-pressure standby control when the first command pressure is higher than the value of the pressing force of the piston and lower than a value corresponding to the third predetermined value. 
 
     
     
       7. A control apparatus for a vehicle, the vehicle including
 a transmission; 
 a fluid coupling provided between the transmission and a power source; and 
 a lockup clutch configured to directly couple an input member and an output member of the fluid coupling by supply of a control oil pressure to a control oil chamber in the fluid coupling, 
 the control apparatus comprising
 an electronic control unit configured to:
 perform lockup clutch release control for lowering a command pressure for the control oil pressure to release the lockup clutch, 
 perform lockup clutch engagement control for raising the command pressure for the control oil pressure to engage the lockup clutch, 
 perform the lockup clutch engagement control in sequence of fast fill control, constant-pressure standby control and command pressure raising control; and 
 start the lockup clutch engagement control from one of the fast fill control and the command pressure raising control which is later in sequence than the other, as a first command pressure rises, in making a transition to the lockup clutch engagement control during the lockup clutch release control the first command pressure being the command pressure for the control oil pressure at a transition time point for making the transition to the lockup clutch engagement control. 
 
 
 
     
     
       8. The control apparatus for the vehicle according to  claim 7 , wherein
 the fast fill control is control for raising the command pressure for the control oil pressure to a first predetermined value set in advance and supplying the control oil pressure to the control oil chamber, 
 the constant-pressure standby control is control for making the command pressure for the control oil pressure equal to a second predetermined value set in advance and causing the command pressure for the control oil pressure to stand by for a predetermined time, the second predetermined value is lower than the first predetermined value, and 
 the command pressure raising control is control for raising the command pressure for the control oil pressure in accordance with a torque capacity that is needed to engage the lockup clutch. 
 
     
     
       9. The control apparatus for the vehicle according to  claim 7 , wherein
 the electronic control unit is configured to start the lockup clutch engagement control from the command pressure raising control when the first command pressure is equal to or higher than a third predetermined value that is needed to carry out packing for narrowing a pack clearance of the lockup clutch. 
 
     
     
       10. The control apparatus for the vehicle according to  claim 9 , wherein
 the electronic control unit is configured to perform the lockup clutch release control until the command pressure for the control oil pressure once becomes equal to zero and then to start the fast fill control, in performing the lockup clutch engagement control from the fast fill control. 
 
     
     
       11. A control method for a vehicle, the vehicle including
 a transmission, 
 a fluid coupling that is provided between the transmission and a power source; and 
 a lockup clutch that is configured to directly couple an input member and an output member of the fluid coupling by supply of a control oil pressure to a control oil chamber in the fluid coupling, and 
 an electronic control unit, 
 the control method comprising:
 performing, by the electronic control unit, lockup clutch release control for lowering a command pressure for the control oil pressure to release the lockup clutch, by the electronic control unit; 
 performing, by the electronic control unit, lockup clutch engagement control for raising the command pressure for the control oil pressure to engage the lockup clutch, by the electronic control unit, the lockup clutch engagement control being performed in sequence of fast fill control, constant-pressure standby control and command pressure raising control; and 
 starting, by the electronic control unit, the lockup clutch engagement control from one of the fast fill control and the command pressure raising control which is later in sequence than the other, as a first command pressure rises, in making a transition to the lockup clutch engagement control during the lockup clutch release control, the first command pressure being the command pressure for the control oil pressure at a transition time point for making the transition to the lockup clutch engagement control. 
 
 
     
     
       12. The control method for the vehicle according to  claim 11 , wherein
 the fast fill control is control for raising the command pressure for the control oil pressure to a first predetermined value set in advance and supplying the control oil pressure to the control oil chamber, 
 the constant-pressure standby control is control for making the command pressure for the control oil pressure equal to a second predetermined value set in advance and causing the command pressure for the control oil pressure to stand by for a predetermined time, the second predetermined value is lower than the first predetermined value, and 
 the command pressure raising control is control for raising the command pressure of the control oil pressure in accordance with a torque capacity that is needed to engage the lockup clutch. 
 
     
     
       13. The control method for the vehicle according to  claim 11 , wherein
 the lockup clutch engagement control is started from the command pressure raising control by the electronic control unit when the first command pressure is equal to or higher than a third predetermined value that is needed to carry out packing for narrowing a pack clearance of the lockup clutch. 
 
     
     
       14. The control method for the vehicle according to  claim 11 , wherein
 the lockup clutch release control is performed by the electronic control unit until the command pressure for the control oil pressure once becomes equal to zero, and then the fast fill control is started by the electronic control unit, in performing the lockup clutch engagement control from the fast fill control. 
 
     
     
       15. A vehicle comprising:
 a transmission; 
 a fluid coupling that is provided between the transmission and a power source; 
 a lockup clutch that is configured to directly couple an input member and an output member of the fluid coupling by supply of a control oil pressure to a control oil chamber in the fluid coupling; and 
 an electronic control unit configured to perform lockup clutch release control for lowering a command pressure for the control oil pressure to release the lockup clutch, 
 the electronic control unit being configured to perform lockup clutch engagement control for raising the command pressure for the control oil pressure to engage the lockup clutch, 
 the electronic control unit being configured such that the lockup clutch engagement control is performed in sequence of fast fill control, constant-pressure standby control and command pressure raising control, and 
 the electronic control unit being configured to start the lockup clutch engagement control from the command pressure raising control when a first command pressure is equal to or higher than a third predetermined value, start the lockup clutch engagement control from the constant-pressure standby control when the first command pressure is lower than the third predetermined value and equal to or higher than a fourth predetermined value, and start the lockup clutch engagement control from the fast fill control when the first command pressure is lower than the fourth predetermined value, in making a transition to the lockup clutch engagement control during the lockup clutch release control, the first command pressure being the command pressure for the control oil pressure at a transition time point for making the transition to the lockup clutch engagement control. 
 
     
     
       16. The vehicle according to  claim 15 , wherein
 the third predetermined value is a value that is needed to carry out packing for narrowing a pack clearance of the lockup clutch, and the fourth predetermined value is a value of a pressing force of a piston, the pressing force of the piston is generated by the command pressure, the value of the pressing force of the piston is equal to a value of an urging force of a return spring.